Refracting cover-glass for automobile-headlights.



H. P. GAGE & E. PASCUCCI.

REFBACTING COVER GLASS FOR AUTOMOBILE HEADLIGHTS.

APPLICATION FILED DEC. 12. 1915.

LQ%3,399 Patented Oct. 16, 1917.

2 SHEETS-SHEET I.

Wihwoaw H. P. GAGE & E. PASCUCCI.

REFRACTING COVER GLASS FOR AUTOMOBILE HEADLIGHTS.

APPLICATION FILED DEC. l2. l9l6.

Patented. Oct. 16,1917.

2 SHEETSSHEET 2.

fjwua'nl'oz eras rarnr enrich.

HEETBY PHELPS GAGE AND EMILIO PASCUCCI, 0F GOBNING, NEW YORK, ASSIGNORS1'0 GOBNING GLASS WORKS, 0F COBNING, NEW YORK, A GORPORATION OF NEWYORK.

il,24l3,899.

Specification of Letters Patent.

Patented Oct. 316, 1911 7.

Application filed December 12,1918. Serial No. 136,434.

To all whom it may concern:

Be it known that we, HENRY Pnnnrs GAGE and EMiLIo PASOUCCI, citizens ofthe United States of America, and residents of the city of Corning andState of New York, have invented certain new and useful Improvements inEefracting Cover-Glasses for Automobile Headlights, of which thefollowing is a specification.

Our invention has for its object to provide a construction in automobileheadlights which will more fully meet the requirements than glasses nowin use.

It is well known that with automobile headlights the problem presentedis to illuminate the road a sufficient distance in front of the machinewithout at the same time producing blinding glare in the eyes of anyapproaching driver. For this purpose we propose to place on the coverglass a plurality of refracting ribs whereby part or all of the lightthrown forward by the reflector will be bent and diffused in definitedesirable directions.

We prefer to form the diffusing ribs cylindrical and with axes inclinedto the opposite face of the coverglass, so that such ribs not only giveside diffusion of light projected thereby but deflect the lightdownwardly by an amount depending on the inclination of their axes tothe opposite face of the glass. Furthermore, this is advantageous inthat side light is usually demanded immediately in front of the vehicle,in order that the user cf the headlight may be enabled to see the entirewidth of the road and especially the ditches to the side of the road.

In the form of the invention first to be described,-the inner face ofthe cover glass has formed thereon a plurality of horizontal rows ofvertical ribs, each rib being in the form of a cylindrical ungula, theaxis of which is at an angle to the face on which the ungula is placed(as well as at an angle to the opposite face), thus leaving plane cuspedshaped portions in each row between the several ribs thereon.

In this form of cover glass the ii ght which passes through withoutdiffusion does not pass through as a single beam, but in the form of anumber of rays, the points at which such rays pass through thecoverglass being separated by the interposed diffusing ribs, so that thecover-glass, as it were, instead of perinittingithe passage of a uniformbundle permits the passage of a plurality of such bundles, each beingrelatively small, whereby the glare is reduced.

In another form of cover-glass to be described, the difi'using ribs arecylindrical ungulas whose axes are parallel with the face on which theyare placed, the edges of the ungulas being in contact with each other,so that in this form, no light is allowed to pass between the ribs.

Both the first and second forms of coverglass here described, are partof one invention which consists in a means of producin downwarddeflection combined with side di fusion by means of diffusing ribs. Asstated, in forms of cover-glass, we prefer to form the diffusing ribscylindrical, and with axes inclined to the optic axis of the system(which in practice may be considered horizontal), of which the glass isto be a part, or more specifically, with axes inclined to the oppositeface of the cover-glass, so that such ribs not only give side diffusionof light projected thereby by an amount depending upon the anglesubtended between the tangents to the surface of the diffusing ribs attheir extreme edges, but they also deflect the light passingtherethrough downward by an amount depending upon the inclination oftheir axes to the opposite face of the cover-glass In either form theribs may cover all. or a part of one surface of the glass. If the latterconstruction be adopted, the ribs are by preference placed upon thecentral portion of the glass, and in the path of the rays projectedforwardly directly from the lens. The former construction isadvantageous under certain conditions, however, in that all of the lightprojected forward by the reflector is deflected downward, therebyeliminating the possibility of glare in the eyes of drivers approachingthe headlight.

Our invention further consists in the several features thereof as willbe hereinafter more fully described.

Referring to the accompanying drawings in which corresponding parts aredesignated by corresponding marks of reference,

Figure l is a section through a headlight screen having one form of ourinvention applied thereto.

Fig. 2 is a fragmental rear view of the cover-glass shown therein, andforming subject-matter of this invention.

Fig. 3 is a fragmental horizontal section therethrough.

Fig. 4 is a vertical section through the glass shown in Fig. 2.

Fig. 5 is a vertical section through a modified form of the glass shownin the above figures.

Fig. 6 is a fragmental rear view of the second form of headlight glassforming subject-matter on this invention.

Fig. 7 is a horizontal section through the glass shown in Fig. 6.

Fig. 8 is a vertical section through the glass shown in Fig. 6.

In these drawings the headlight may be of any approved construction, andis shown as consisting of a lamp B properly located in respect to thereflector A to project a more or less parallel beam.

In front of the reflector is located the cover-glass D through whichpasses the light thrown forwardly by the reflector. In practice, whenthe bulb is in the focus of the parabolic reflector, the beam projectedby the reflector is slightly divergent around the axis of the opticalsystem formed by the lamp and reflector, but this divergence withparabolic reflectors is not suiiicient to meet certain requirements asto side spread. If the bulb is thrown out of focus, with respect to theparabolic reflector, suiiicient side spread may be obtained, but thevertical spread will be too great and other dis-ad vantageous conditionsof light distribution will occur.

To increase the side spread, we form on one (and preferably) the innerface of the (lever-glass, a series of vertical ribs (1 so shaped as togive a lateral spread to light passing therethrough.

By preference the didusing ribs form cylindrical ungulas, thecylindrical axes of which dd are inclined to the opposite face of theglass, or, to express it differently, are, if the glass is flat,inclined to its plane, and are not normal to the optical axis a-a of thesystem, whereby light refracted by the ribs is not only diffusedlaterally but is bent vertically downward to a greater or less extentupon the ground or roadway in front of the vehicle, and not upward intothe face of the approaching driver. Further more, these ribs arearranged in horizontal tiers or rows, whereby the maximum thickness ofthe ribs is kept within proper limits. The ribs in one row are staggeredin respect to the ribs in the adjacent rows. This staggering is.however, not an cs ntial feature of the invention, but is employedmainly for -the sake of pleasing appearance.

lessees This arrangement, if the axes of the ungulas are inclined to theface on which they are placed, as shown in Figs. 1 to 5, breaks the faceof the cover-glass into horizontal rows, each row consisting ofalternate diffusing faces and plane faces, the latter, marked e, beinglocated between the difiusing ribs and being inverted cusps. With thisconstruction the non-diffused light passing through the cover-glass,instead of being a solid beam, is composed of a plurality of rays, thepoints at which the several rays pass through the cover-glass beingseparated from each other, so'that to some extent the glare due to thenon-diflused rays is reduced. The ribs themselves will not produceglare, in that the light issuing therefrom is directed downward.

This construction results in the non-didusive surfaces of the glassserving to project a beam which serves for the distant illumination ofthe read, while the downward defiection produced by the ribs, combinedwith the diffusion caused thereby illuminates a comparatively wide stripimmediately in front of the car. This side diffusion is not so muchneeded in the distant beam, due to the fact that the beam as projectedby the reflector is in itself slightly dispersive and therefore at adistance covers a sufficiently wide path.

if desired, the cover-glass may have one of its surfaces so shaped as toform a series of prisms whose bases are downward, and a row of ribs maybe superimposed on the inclined refracting faces of one or more of theseprisms. An example of such construction is shown in Fig. 5, in which theaxes of the ungulas '02 are inclined to the refracting faces 6' of theprisms on which they are placed, although this specific form is not ofour invention, it being the invention of another. With such aconstruction the faces 6 while non-difi'usive, are refracting and serveto project the light passing therethrough downward, but not to the sameextent as is done by the ribs.

in the second described cover-glass, (viz, that shown in Figs. 6 to 8),the series of vertical ribs are so arranged upon the glass that nonon-retracting portions are left between them through which lightprojected by the reflector may pass without lateral diffusion, or inother words, the ribs are formed so that they are in contact with eachother. By preference, in this form of the invention, the difi'using ribsform cylindrical ungulas, the cylindrical axes of which W d are parallelto the surfaces in which they are superposed and inclined to theopposite face of the glass. This, in the figures last referred to, isaccomplished by forming the cover-glass with a series of substantiallyhorizontal rows of prisms thereon, and su poi-imposing the ribs (Z onsuch rows, the

cylindrical axis d"-d of the ribs being parallel with the retractingprism surfaces 9' on which they are placed.

With this construction, all of the light projected by the reflector in aparallel beam will be directed downward, by reason of the prisms and ofthe inclination of the cylindrical axes of the ribs, and cannot causeglare. The horizontal diifusion produced by the ribs, serves toilluminate a comparatively wide strip of road immediately in front ofthe car.

It will be noted that in the construction shown in Figs. 1 to 5, thebases of the ungulas are of greater depth thahitheir upper edges, whilein Figs. 6 to 8, the ungulas have equal depth at top and bottom; that inFigs. 1 to 4 the downward deflection is due entirely to this peculiarityof the ribs; that in Figs. 6 to 8 the downward deflection is due to theprisms on which the ungulas are superimposed, and that in Fig. 5 it isdue to both the ungulas and to the ribs. From this it follows that thecharacter oi the projected beam may be Widely varied by changing thedeflection, due to the several causes, and it will also be understoodthat the amount of side spread produced by the ribs may be varied byvarying the radius on which the surfaces of the ribs are formed; thatthe downward projection may be varied by varying the angle made by theaxes on which the ribs are struck and the opposite side of thecover-glass, and that the proportion of the total li 'ht projected fromthe mirror which is difi ilsed may be varied by changing the proportionof the surface or the cover-glass covered by the ribs.

Having thus described our invention, what we claim and desire to secureby Letters Patent is,

1. A cover-glass for an automobile headlight having on a face thereof aplurality of ribs, the axes of which are inclined to the opposite faceof the glass and the faces of which in horizontal cross-section arecurved to produce side dispersion, while causing a downward deflectionof the rays passing therethrough.

2. A cover-glass having .on a face thereof cylindrical ungulas arrangedin horizontal rows, the cylindrical axes of the ungulas being inclinedto the opposite face of the coverglass.

3. A flat cover-glass having thereon vertical ribs, whose outer faces inhorizontal section are convex and in vertical section are inclined tothe plane of the glass to produce downward divergence of the rayspassing therethrough when the glass is vertical.

In testimony whereof we have signed our names.

HENRY PHELPS GAGE. EMILIO PASCUCCI.

